was signed in the London Customs Convention on 5 September 1944, just days before the Belgian government returned to Brussels after the liberation. The Benelux Customs Union was a major extension of a pre-war union between Belgium and Luxembourg, and would later form the basis of the Benelux Economic Union after 1958. Authority Unlike many other governments in exile, which were forced to rely exclusively on financial support from the Allies, the Belgian government in exile could fund itself independently. In large part, this was due to the fact that the government in exile retained control of most of the Belgian national gold reserves. These had been moved secretly to Britain in May 1940 aboard the naval trawler A4, and provided an important asset. The Belgian government was also in control of the Belgian Congo, which exported large amounts of raw materials (including rubber, gold and uranium) which the Allies relied on for the war effort. The Belgian government published its own official journal, the Moniteur Belge (Official Government), from London. Stances Relations with Leopold III Despite being a constitutional monarch, the King of the Belgians had occupied an important political role within Belgium before the war. The decision of Leopold III to surrender to the Germans – without consulting his own ministers – outraged the Belgian cabinet. The King's apparent opposition to it undermined its credibility and legitimacy. For the first years of the war, the King was viewed as an alternative source of "government" by many, including figures in the Free Belgian military, which served to further undermine the official government in London. Later in the war, the government changed its position to be less belligerent towards the king. Belgian propaganda of the time instead emphasized the King's position as "martyr" and prisoner-of-war and presented him as sharing the same sufferings as the occupied country. In a radio speech on 10 May 1941 (the first anniversary of the German invasion), Pierlot called for Belgians to "rally around the prisoner-King. He personifies our murdered country. Be as loyal to him as we are here." According to the Constitution of 1831, the Belgian government was allowed to override the wishes of the King if he had been declared incompetent to reign. On 28 May 1940, under pressure from the French government, the Pierlot government in France declared the King to be under the power of the invaders and unfit to